Non-icing carburetor



June 26, 1956 R. NYE 2,752,132

NON-ICING CARBURETOR Filed April 17, 1953 Raga V5:

IN V EN TOR.

I; Fla 2 United States Patent NON-ICING CARBURETOR Ray Nye, Detroit, Mich., assignor to Holley Carburetor Company, Detroit, Mich., a corporation of Michigan Application April 17, 1953, Serial No. 349,435

4 Claims. (Cl. 261-23) The object of this invention is to reduce the tendency for a throttle on an automobile carburetor to freeze when the throttle is almost closed due to the action of the low speed nozzle.

A secondary object is to permit an engine to start and to keep running even if the throttle does become frozen so that the throttle cannot be moved.

Figure 1 is a partial cross-section taken on plane 11 of Figure 2.

Figure 2 is a plan view of the flange looking up.

Figure 3 is a similar view to Figure 2 with a modification added.

In the figures:

FIGURES 1 AND 2 A double carburetor is intended in both cases although only one throttle is illustrated. This particular carburetor is intended for use with a V-8 engine, one barrel for each bank of four, cylinders and one inlet manifold for each bank.

50 is one arm of a double inlet manifold, the other arm being right behind it and identical with 50.

10 is the main air venturi, being one of the two identical venturis of the two identical carburetors.

12 is one of the two main fuel nozzles and discharges into the throat of the venturi 10.

The other nozzles are not shown.

13 and 14 are the two low speed fuel nozzles for the two carburetors which derive their fuel from the same source, the float chamber 51, as the main fuel nozzle 12 (shown) and for the other main nozzle (not shown).

15 is one of the two mixture outlets above the throttle 16, which is one of the two butterfly throttles and is located in the mixture outlet 15.

17 is the other throttle.

Mixture outlet 45 is on the engine side of throttle 16 and mixture outlet 47 is on the engine side of throttle 17 of the other carburetor.

Orifices 1S and 20 are two low speed fuel outlets from the low speed passage 14 connected to mixture outlet 15 when inactive and discharging into mixture outlet 45 when the butterfly throttle is first moved away from idle, so that they are subjected to the eddy downstream of the upstream edge of butterfly throttle 16 which creates a. high suction effect. With the throttle 16 as shown air enters the two orifices into low speed fuel passage 14.

22 and 23 are the two low speed fuel adjustments regulating flow from low speed fuel passages 13 and 14 to mixture outlets 45 and 47, respectively.

24 is a restriction in the bottom of low speed fuel passage 14. I

25 is a restriction in the bottom low speed fuel passage 13.

'IN FIGURE 2 26 and 27 are two identical slotsconducting low speed fuel to two mixture outlets 45 and 47 from the two restrictions 24 and 25 in the low speed fuel passages 13 and 14.

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28 is an air by-pass around both throttles.

29 and 31 are two slots discharging air from this by-pass passage 28 into mixture outlets 45 and 47 on the engine side of the throttle, and

39 is a slot which is one of the air entrances for the by-pass air from the mixing chamber 15 above the throttle 16.

The slots 25, 29, 39 and one similar to 39 (not shown), are formed in the casting 53 which separates the casting 52 containing the float chamber 51 from the inlet manifold 50.

Casting 53 is referred to as the throttle housing.

The by-pass 28 carries the ice-forming low speed air away from the upstream lip of butterfly throttle 16.

A second connecting passage to 33 having two outlets and inlets 54 are shown to utilize the fluctuating differential pressure between the pressures in the two mixing chambers 45 and 47 which pressures are always out of step. The sources of the fluctuating pressure in passage 33 are the two passages 54 and 55. As shown by the two double arrows, whenever one block of cylinders is drawing mixture at the maximum, the minimum flow takes place in the other. The purpose of this transfer of below throttle mixture is to stir up the slow moving mass of air and fuel which are no longer mixed at the lip of the throttle.

An improvement in distribution occurs because of this fluctuation which helps distribution and is most marked when two throttles are closed.

FIGURE 3 The low speed restriction 24 (Fig. l) is connected with mixture outlet 45 through a semi-circular groove 40 with a slot 44 (corresponding to slot 26 of Figures 1 and 2); a similar semi-circular groove 42 and a slot 45 also connects restriction 24 with mixture outlet 47.

Air passages 28 and outlets 29 and 31 are identical with 28 and outlets 29 and 31 (shown in Figures 1 and 2) are also identical, as is cross passage 33 and its two outlets and inlets 54 and 55, for the fluctuation in pressure between the two pressures existing in two mixture outlets 45 and 47.

Operation With the throttle 16 closed, air flows around throttle 16 through and across slot 39 down by-pass 28 across slots 29 and 31 to engine side of throttle 16 so that the throttle 16 admits little, if any, air. Meanwhile, fuel flows past the needle valve 22. and also through the restriction 24 and across slot 26, both leading to the mixture outlet 45. The idle passage 24 and slot 26 transfer fuel, that would otherwise cause ice to form, to the face of the manifold 51 on which face ice is less likely to form as this manifold is warmer than 53, the second housing.

' 1N FIGURE 2 Passages 26 and 29that is, the fuel and air passages, are close together and passage outlet 55 from passage 33 is remote from the fuel outlet passage 26.

IN FIGURE 3 Passages 44 and 29 are not so close, and the fuel fans out into the air and the outlets 54 and 55 are adjacent to the fuel outlets 44 and 46 so that a better distribution of fuel and air results.

This improvement is found to be important under low speed operating conditions. If an attempt to move throttle 16 is made and it fails to open due to the low speed fuel issuing from orifices 18 and 24) thus causing the throttle to freeze, fuel will continue to flow past the needle 22 and also along the slot 40 through the restriction 24.

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As the fuel sprays out of outlet slot 44 into mixture outlet 45, it is subjected to the rapid fluctuations in flow into and out of passage 55 from the mixture outlet 47 which creates turbulence.

The passages 54 and 55 help keep fuel in suspension. The passage 33 is a deadend passage operating the econo mizer diaphragm (not part of this invention);

The air by-pass creates rotation; the pulsating flow creates turbulence A turbulent rotation is'the end result which favors uniform distribution at low engine speeds between the various cylinders.

What I claim is: V a

1. In an internal combustion engine having an inlet manifold and a carburetor mounted thereon, an air entrance to said carburetor, a mixing chamber, a first housing containing said chamber, a mixture outlet and V a butterfly throttle, a second housing therefor interposed between the first housing and said manifold, and having a mixture passage therein, a low speed fuel passage in the firstrand second housings and having an outlet subjected to the suction at the upstream lip of the butterfly throttle when it is first moved away fromtits closed position in said second housing, an air by-pass around said throttle located in said second housing, a flat lower surface to said first housing and a similar one for the upper surface of said second housing, an upper slot in said upper surface of said second housing forming a passage with the lower surface of the first housing extending from said by-pass into the mixing chamber above said throttle, a flat lower surface on said second housing and a similar one for the manifold, a lower slot in said bottom surface of the second housing forming a passage extending from said air by-pass into the mixture outlet below said throttle, a second slot in the bottom face of said second housing also forming a similar passage extending from said low speed fuel passage into the mixture outlet below said throttle, and in which the lower slot of the air by-pass is located so as to enter the mixture outlet non-radially to the mixture outlet so as to rotate the mixture therein.

retors, one mounted on each manifold, two air entrances for each carburetor, two mixing chambers, a first housing containing said chambers, two mixture outlets, a second housing therefor interposed between the first housing and said manifolds, a throttle shaft therein, two butterfly throttles mounted thereon, two low speed fuel passages in said first and second housings, each having an outlet subjected to the suction at the upstream lips of said butterfly throttles when they are first moved away from their closed position in said housing, an air by-pass around said two throttles locatedin saidsecond housing, a flat lower surface on said first housing and a flat upper surface in said second housing, an upper slot in said upper surface forming a passage with the lower surface of'the first housing and a similar slot in the lower surface of the second housing, with the upper surface of said manifold extending from said air by-pass into the mixture chamber below said throttle; two similar slots in the bottom 'face of said second housing also forming with the flat upper'surface of said manifoldttwo similar fuel passages extending from said two low-speed j fuel passages into the mixture outlets below said two 2. In an internal combustion engine having an inlet 7 manifold and a carburetor mounted thereon, an air entrancerto said carburetor, a mixing chamber, a first housing containing said chamber, 'a mixture outlet and a butterfly throttle, a second housing therefor interposed between the first housing and said manifold, and having a mixture passage therein, a low speed fuel passage in the first and second housings and having an outlet subjected to the suction at the upstream lip of the butterfly throttle when it is first moved away from its closed position in said second housing, an air by-pass around said throttle located in said second housing, a flat lower surface to said first housing and a similar one for the upper surface in said second housing, an upper slot in said upper surface of said second housing forming a passage with the lower surface of the first housing extending from said by-pass into the mixing chamber above said throttle, a flat lower surface on said second housing and a similar one for the manifold, a lower slot in said bottom surface of the second housing forming'a passage extending from said air by-pass into the mixture outlet below said throttle, a second slot in the bottom face. of said second housing also forming a similar passage extending from said low speed fuel passage into the mixture outlet below said throttle, and in which the fuel slot in the bottom face of second housing extends around the mixture outlet passage so that it discharges almost 180 away from the entry point for the by -pass air.

3. In an internal combustion engine having two inlet 7 manifolds having a flat upper surface and two carbuthrottles, and in which there is a third, slot in the bottom face of said second housing forming with the face of said manifold a similar passage; said passage transmitting the differential pressure between the two'mixture outlets below said throttle to create turbulence therein, and in which the differential pressure, is admitted adjacent to the entry of the two low speed fuel slots int said mixture outlet.

4. In an internal combustion engine having two inlet manifolds having a fiat upper surface and two carburetors, one mounted on each manifold, two air entrances for each carburetor, two mixing chambers, a first housing containing said chambers, two mixture outlets, a second housing therefor interposed between the first housing and said manifolds, a throttle shaft therein, two butterfly throttles mounted thereon, two low speed fuel passages in said first and second housings, each having an outlet subjected to the suction at the upstream lips of said butterfly throttles when they are first moved away from their closed position in said housing, an air by-pass around said two throttles located in said second housings, a flat lower surface on said first housing and a flat upper surface in said second housing, an upper slot in said upper surface forming a passage with the lower surface of the first housing and a similar slot in the lower surface of the second housing, with the upper surface of said manifold extending from said air by-pass into the mixture chamber below said throttle; two similar slots in the bottom face of said second housing also forming with the flat upper surface of said manifold two similar fuel passages extending from said two low-speed fuel passages into the mixture outlets below said two throttles, and in which there is a third slot in the bottom face of said second housing forming with the face of saidmanifold a similar passage, said passage transmitting the differential pressure between the two mixture References Cited in the file of this patent UNITED STATES PATENTS 2,031,709 Hunt Feb. 25, 1936 2,345,168 Wirth et a1. Mar. 28, 1944 2,376,228 Brown May 15, 1945 ira-v 

